<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>边框合并</title>
    <style>
        table{
            width: 500px;
            height: 500px;
            /* 第一个参数 boder-width 第二个参数 border-style 第三个参数border-color */
            /* border-style的取值 solid 实线  dash 虚线  dotted 点线 none 无 */
            /* border-top border-top-style之类的属性也有 */
            border: 1px solid red;
            text-align: center;
            border-collapse: collapse;
        }
        td{
            border: 1px solid red;
        }
    </style>
</head>
<body>
    <table>
        <tr>
            <td>test1</td>
            <td>test1</td>
            <td>test1</td>
        </tr>
        <tr>
            <td>test2</td>
            <td>test2</td>
            <td>test2</td>
        </tr>
        <tr>
            <td>test3</td>
            <td>test3</td>
            <td>test3</td>
        </tr>
    </table>
</body>
</html>